From Infogalactic: the planetary knowledge core
ETTN Codes can be used only for electronic text files. Any publisher, university, researcher or academician could ask for unique code for his/her electronic text generated by Magnanimitas Assn.
ETTN Code consists of 5 parts - AAA-BB-CCCCC-DD-F
- AAA (3-digit) is classified by the Statistical classification of economic activities in the European Community (NACE) and shows the focus of text
- BB (2-digit) – the year of ETTN generating for a text
- CCCCC (5-digit) – special identification code for text
- DD (2-digit) – month of ETTN generating for a text
- F (1-digit) – check digit